A highly sensitive and selective fluorescent Cu²⁺ sensor synthesized with silica nanoparticles

A novel fluorescent nanosensor for the determination of Cu²⁺ was synthesized with N-(quinoline-8-yl)-2-(3-triethoxysilyl-propylamino)-acetamide (QlOEt) grafted onto the surface of silica nanoparticles (SiNPs) using the reverse microemulsion method. Spherical SiNPs were used as substrate and QlOEt was used simultaneously as the binding and readout system for Cu²⁺. This sensor has been realized as a highly sensitive and selective technique for the detection and quantification of trace amounts of Cu²⁺. The probe exhibits a dynamic response range for Cu²⁺ from 2.0 × 10 ^-6 to 2.0 × 10^-5M, with a detection limit of 3.8 × 10^-7M. Other alkali, alkaline earth, and transitional metal ions including Li⁺, K⁺, Mg²⁺, Ca²⁺, Sr²⁺, Mn²⁺, Zn²⁺, Mo⁶⁺, Pb ²⁺, Ag⁺ had no significant interference on Cu²⁺ determination. Poisonous and flammable reagents are avoided during the synthesis of this nanosensor. Therefore the strategy explored in this work can be extended to the synthesis of other chemo-and biosensors for direct detection of specific targets in an intracellular environment.